Effect of short-term intervention on infraspinatus muscle activity during throwing motion and physical examination in baseball players with throwing disorder

Article type: Research Article

Authors: Kotoshiba, Somu^a | Maeda, Noriaki^{a; *} | Urabe, Yukio^a | Sasadai, Junpei^a | Aramaki, Kei^b | Sumida, Ryohei^b | Yanase, Kazutaka^c | Hara, Masafumi^{c; d}

Affiliations: [a] Division of Sport Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan | [b] Department of Rehabilitation, Hisatsune Hospital, Fukuoka, Japan | [c] Hara Baseball Medical Institute, Fukuoka, Japan | [d] Department of Orthopedic Surgery, Hisatsune Hospital, Fukuoka, Japan

Correspondence: [*] Corresponding author: Noriaki Maeda, %****␣ies-28-ies193192_temp.tex␣Line␣25␣**** Division of Sport Rehabilitation, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan. Tel.: +81 82 257 5410; Fax: +81 82 257 5344; E-mail: norimmi@hiroshima-u.ac.jp.

Abstract: BACKGROUND: No studies so far have investigated the effectiveness of the short-term intervention on the capacity of the ISP during throwing motion in baseball player with throwing disorder. OBJECTIVE: To investigate the effectiveness of short-term intervention on ISP during throwing motion and of physical examination in baseball player with throwing disorder. METHODS: Twenty-seven male baseball players with throwing disorder were hospitalized for 1 week and received physical therapy for 1 hour a day. In the pre- and post-hospitalized period, participants were evaluated using physical examinations (Hara test) and ISP and posterior deltoid muscle activity during throwing motion. RESULTS: The ISP during the late-cocking phase and follow-through phase at the time of hospital discharge were significantly greater than that at the hospital admission (P< 0.05). The effect sizes revealed large effects for follow through phase (r=-0.60). The positive rate of the Hara test decreased significantly in all examination items except scapula-spine distance, subacromial impingement test, and hyper-external rotation test. CONCLUSIONS: The ISP in throwing motion is important to the stability of the glenohumeral joint during follow-through phase. Our results indicated that the improvements in the physical examination reflected favorably on the ISP during the throwing motion.

Keywords: Throwing disorder, baseball, infraspinatus

DOI: 10.3233/IES-193192

Journal: Isokinetics and Exercise Science, vol. 28, no. 1, pp. 91-99, 2020